engine cuts out over half throttle

i have a pickup with a rebuilt 70's chevy 350 i slapped a rochester from a 79 firebird on it (301) and all seemed to run fine. now i try and drive it around and anything over half throttle it acts like it cant go there. and cuts out and bogs out. what could be the problem. fuel? probally but how do i test for that? can i buy a inline fuel pressure gauge?

If it's a QJet carb. the secondary air valves (top/rear flaps)are likely opening too quick or the rear jets are clogged.
Another problem is the fuel filter clogging with rust on older vehicles.
QJet carbs can be troublesome if you're not very, very familiar with them. A rebuilt piece with warranty from a reputable auto parts store is the quickest path to sucess in most cases.